1. Field of the Invention
This invention relates to improvements in well bore drilling operations and more particularly, but not by way of limitation, to a means for maintaining continuous air circulation downhole during an air drilling operation.
2. Description of the Prior Art
In some well bore drilling operations, air is utilized as the drilling medium, and the air is circulated downwardly through the drill pipe for excavation of the well bore and to maintain circulation of the down hole water or fluids in order to prevent the water from interfering with the air drilling operation. Each time the drilling operation is interrupted for addition a section of drill pipe to the drill string, the circulation of the air to the bottom of the well bore is interrupted. In instances wherein the well bore drilling operation is being done in an area wherein the water table is encountered in the drilling of the well bore, the interruption of the air pressure is a great disadvantage in that the water quickly fills the hole, and the resumption of the circulation of the air downwardly through the drill stem cannot remove the reservoir of water from the bottom of the well bore, nor can the water be pumped out as fast as it enters the well bore.